Age-Adjusted in-Hospital Mortality in Patients with COVID-19 Infection: Impact of the Presence of Multiple Comorbidities.

Background: Mortality has been indicated to be high in patients with underlying diseases. This study aimed to examine the comorbidities is associated with a higher risk of death during the hospital course.

Methods: We retrospectively evaluated the risk of in-hospital death in 1368 patients with COVID-19 admitted to 5 academic hospitals in Tehran between February 20 and June 13, 2020. We also assessed the composite end-point of intensive care unit admission, invasive ventilation, and death. The Cox proportional survival model determined the potential comorbidities associated with deaths and serious outcomes.

Results: The retrospective follow-up of patients with COVID-19 over 5 months indicated 280 in-hospital deaths. Patients with diabetes (risk ratio (RR), 1.47 (95% CI, 1.10-1.95); P = 0.008) and chronic kidney disease (RR, 1.72 (95% CI, 1.16-2.56); P = 0.007) showed higher in-hospital mortality. Upon stratifying data by age, patients aged ˂65 years showed a greater risk of in-hospital death in the presence of 2 (hazard ratio (HR), 2.68 (95% CI, 1.46-4.95); P = 0.002) or more (HR, 3.47 (95% CI, 1.69-7.12); P = 0.001) comorbidities, compared with those aged ≥ 65 years.

Conclusion: Having ≥ 2 comorbidities in nonelderly patients is associated with a greater risk of death during hospitalization. To reduce the mortality of COVID-19 infection, younger patients with underlying diseases should be the focus of attention for prevention strategies.